All the ones who can beat Itachi:
Nagato-I know this will fire up an argument right away but seriously he couldn't have beat him that last time without naruto and bees help...he need their most powerful attacks too, and not to mention this simple fact this is the absolute reason Nagato would beat Itachi is every one listening...Nagato has so many summon animals not too mention his others pains I mean how many does he have 6? I can't remeber but anyway the only way Itachi could dispose of them would be with the amatarasu or susano' since i think its pretty obvious the tsukynomi would be useless and these two moves would cause Itachis eyes to burst with blood and tired him down before he could destroy all of these things on Nagatos side
Jiraiya- Itachi ran from Jiraiya when they attempted to take naruto so obviously he was afraid of him and he admitted before that that he could not beat him, aside from that with all of Jiraiyas summons that kind of puts itachi in almost the same position he would be in with Nagato
Madara-Although we haven't seen his real power yet I think its safe to assume he is meant to superior alhtough none of us can say for sure